Sequence calculator

Evaluate arithmetic, geometric, and Fibonacci-type sequences — nth term, sum, and term list.

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Fibonacci mode uses arbitrary-precision integers (a₁ and the step field become the two seeds F₁, F₂). Arithmetic/geometric use floating point; |r| < 1 adds the infinite sum. n ≤ 10,000.

How to use

  1. Choose the sequence type.
  2. Enter the starting values and step/ratio.
  3. Set n and read the term, the sum, and the list.

What it supports

Arithmetic a₁, a₁+d, …; geometric a₁·rⁿ⁻¹; Fibonacci-type seeded with your first two terms. Up to 10,000 terms; Fibonacci output stops at 5,000-digit magnitudes. Sums use closed forms where exact; large geometric ratios can overflow to Infinity.

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